Spinal column Flashcards
• a mass of nerve tissue located
in the vertebral cavity from
which 31 pairs of spinal nerves
originate
SPINAL COLUMN
•Protective Coverings of Spinal Cord
• bony structure protecting
the spinal cord
VERTEBRAL COLUMN
• transmits impulses to & from
the brain
• integrating center for spinal
reflexes
SPINAL CORD
•Protective Coverings of Spinal Cord
• layers of connective tissue
coverings that extend
around the spinal cord &
brain
MENINGES
•the space bet. the dura
mater & vertebral column
contains a cushion of fat
& conn. tiss. that help
protect the spinal cord
EPIDURAL SPACE
• the middle layer of the
meninges
• composed of collagen &
elastic fibers arranged
like a “spider’s web”
ARACHNOID MATER
•the space bet. the
arachnoid mater &
dura mater
•contains interstitial
fluid
SUBDURAL SPACE
PIA MATER
• the innermost meninx
• a thin, transparent layer of
collagen & elastic fibers
that adheres to the surface
of the spinal cord & brain
• has numerous blood vessels
•the space bet. the pia
mater & arachnoid
mater
where cerebrospinal
fluid (CSF) circulates
SUBARACHNOID SPACE
•where needle is inserted
for injection of spinal
anesthesia or to remove
CSF during a lumbar
puncture/spinal tap
SUBARACHNOID SPACE
• are named after
adjacent vertebrae
SEGMENTS
• length of the adult
spinal cord ranges
from 16–18 inches
& its diameter is
about 0.75 in. (2
cm)
LENGTH
• it extends from the
medulla oblongata,
the inferior part of
the brain, to the
superior border of
2nd lumbar
vertebra.
LENGHT
• “horse’s tail”
• an array of roots of
spinal nerves at the
inferior end of the
spinal cord
CAUDA EQUINA
•ENLARGEMENTS
•contains nerves that
supply the upper
limbs
CERVICAL ENLARGEMENT
ENLARGEMENTS
•contains nerves
that supply the
lower limbs
LUMBAR ENLARGEMENTS
Internal Structure of Spinal Cord
• a small space that extends the
length of the cord & contains CSF
• continuous with the fourth
ventricle (a space that contains
CSF in the medulla oblongata of
the brain)
CENTRAL CANAL
Internal Structure of Spinal Cord
• contains bundles of myelinated
nerve fibers ascending and
descending through the spinal
cord in separate tracts
WHITE MATTER
Internal Structure of Spinal Cord
• surrounded by white matter
• receives & integrates incoming
& outgoing information & is a
site for integration of reflexes
GRAY MATTER
Internal Structure of Spinal Cord
• an H-shaped or butterfly-
shaped area of gray matter in
the spinal cord
• made up of cell bodies
clustered into nuclei
HORNS
• contain cell bodies of somatic
motor neurons
ANTERIOR/VENTRAL HORNS
• contain cell bodies of
autonomic motor
neurons
• only found in the
thoracic & upper
lumbar segments of
the cord
LATERAL HORNS
• contain cell bodies of somatic
& autonomic sensory neurons
POSTERIOR/DORSAL HORNS
• group of white matter tracts in
the spinal cord
• contain both ascending
(sensory) & descending (motor)
tracts
COLUMN
• consist of myelinated axons
that conduct nerve impulses
upward or toward the brain
ASCENDING (SENSORY) TRACTS
• consist of myelinated axons
that carry nerve impulses from
the brain down the spinal cord
DESCENDING (MOTOR) TRACTS
Structures related to Spinal Nerves
• two bundles of axons that
connect each spinal nerve to a
segment of the cord
ROOTS
• contains motor nerve
fibers/axons that conduct
impulses from the CNS to
muscles & glands
ANTERIOR (VENTRAL) ROOT
• contains sensory nerve
fibers/axons that conduct
nerve impulses for sensations
from the skin, muscles, &
internal organs into the CNS
POSTERIOR (DORSAL) ROOT
• a swelling found on each
posterior root that contains
the cell bodies of sensory
neurons
POSTERIOR ROOT GANGLION
• the portion of the
vertebral column from
which the first cervical
pair of spinal nerves
emerge
ATLAS
• portion of the vertebral column
from which the other spinal
nerves emerge
INTERVERTEBRAL FORAMINA
• an area of skin that provides
sensory input to the CNS via the
posterior roots of one pair of
spinal nerves
DERMATOME
• a network of nerves formed from
the branching of spinal nerves
PLEXUS
• formed by spinal nerves C1 to C4
• innervates the skin & muscles of
the posterior head, neck, upper
part of the shoulders, and the
diaphragm
CERVICAL PLEXUS
• arises from the cervical plexus
• stimulates the diaphragm to
contract
• damage to the spinal cord above
the origin of this nerve may cause
respiratory failure
PHRENIC NERVE
• formed by spinal nerves C5 to T1
• innervates the upper limbs &
several neck & shoulder muscles
• where the median, ulnar & radial
nerves arise
BRACHIAL PLEXUS
• arises from brachial plexus
• innervates the skin & muscles of
posterior arm, forearm, & hand
• may be injured by a faulty deltoid
injection , tight arm cast or
improper use of crutches
RADIAL NERVE
• arises from brachial plexus
• innervates the skin & muscles of
anterior arm, forearm, & hand
• is affected in carpal tunnel
syndrome & often cut during
wrist-slashing suicide attempts
MEDIAN NERVE
• refer to spinal nerves T2 to T11
that do not form plexuses
• extend directly to the structures
they supply: intercostal muscles,
abdominal muscles & skin of the
chest and back
INTERCOSTAL NERVES
• formed by spinal nerves L1 to L4
• innervates the abdominal wall,
external genitals, and part of the
lower limbs
• where the femoral nerve arises
LUMBAR PLEXUS
• also called “lumbosacral plexus”
• formed by spinal nerves L4 to S4
• innervates the buttocks,
perineum, & lower limbs
SACRAL PLEXUS
• arises from sacral plexus
• thickest & longest nerve of the body
• innervates skin & muscles of
posterior thigh, leg & foot
• has two main branches: tibial nerve &
common fibular nerve
SCIATIC NERVES
• may be injured by a faulty gluteal
injection
SCIATIC NERVE
• the route that nerve impulses
follow from a neuron in one part
of the body to other neurons
elsewhere in the body
PATHWAY
• a fast, involuntary sequence of
actions that occurs in response to
a particular stimulus
REFLEX
• refers to a reflex wherein
integration takes place in the
spinal cord gray matter
SPINAL REFLEX
• integration of reflex occurs in the
brain stem rather than the spinal
cord
CRANIAL REFLEX
• a pathway followed by nerve
impulses that produce a reflex
REFLEX ARC
• effector is a skeletal muscle
• e.g., patellar & triceps reflex
SOMATIC REFLEX
effector is a smooth muscle or gland
• e.g., swallowing, urinating,
defecating
AUTONOMIC or VISCERAL REFLEX
